The present disclosure relates to a solid electrolyte, a method of preparing the solid electrolyte, and an electrochemical device. More specifically, the present disclosure relates to, for example, a solid electrolyte suitable for use as an electrolyte in an all solid-state lithium (Li) ion battery, and a method of preparing the same, and various electrochemical devices such as a lithium ion battery using the solid electrolyte.
In recent years, an all solid-state lithium ion battery using a solid electrolyte which is a lithium ion conductor attracts attention, which acts as a secondary battery having a higher safety compared to an existing lithium ion battery using, as an electrolyte, a non-aqueous electrolyte which dissolves a lithium salt into an organic solvent (refer to, for example, Patent Literature 1). That is, the lithium ion conductor constituting the solid electrolyte is a single ion conductor in which only a lithium ion moves so that a side reaction and deterioration of an electrode accompanied thereby hardly take place compared to a secondary battery using a liquid electrolyte. Accordingly, the all solid-state lithium ion battery is a promising entry for a battery for an electric vehicle and a large-sized rechargeable battery.
In particular, the all solid-state lithium ion battery is expected to be preferably used as an in-vehicle higher output electric source because it is highly functional, highly reliable, highly risk-free without liquid spill, can obtain clean energy, is light-weighted, and can obtain higher energy density.
The most important material in this all solid-state lithium ion battery is the solid electrolyte exhibiting the lithium ion conductivity comparable to that of an organic solvent. While a number of solid electrolyte materials have been proposed, the most promising entry with respect to the safety is La2/3−xLi3xTi3 (popular name: LLT) reported by Inaguma, et. al. of its higher lithium ion conductivity (refer to Non-Patent Literature 1).